Interfacial growth in driven diffusive systems

We have studied the growth of interfaces in driven diffusive systems well below the critical temperature by means of Monte Carlo simulations. We consider the region beyond the linear regime and of large values of the external field which has not been explored before. The simulations support the existence of interfacial traveling waves when asymmetry is introduced in the model, a result previously predicted by a linear-stability analysis. Furthermore, the generalization of the Gibbs-Thomson relation is discussed. The results provide evidence that the external field is a stabilizing effect which can be considered as effectively increasing the surface tension.

Effects of external noise on the Swift-Hohenberg Equation

The Swift-Hohenberg equation is studied in the presence of a multiplicative noise. This stochastic equation could describe a situation in which a noise has been superimposed on the temperature gradient between the two plates of a Rayleigh-Bnard cell. A linear stability analysis and numerical simulations show that, in constrast to the additive-noise case, convective structures appear in a regime in which a deterministic analysis predicts a homogeneous solution.

Interfacial instability induced by external fluctuations

The dynamics of an interface separating the two coexistent phases of a binary system in the presence of external fluctuations in temperature is studied. An interfacial instability is obtained for an interface that would be stable in the absence of fluctuations or in the presence of internal fluctuations. Analytical stability analysis and numerical simulations are in accordance with an explanation of these effects in terms of a quenchlike instability induced by fluctuations.

From lattice-gas models to nonlinear diffusion models: A derivation of macroscopic equations and fluctuations

We derive nonlinear diffusion equations and equations containing corrections due to fluctuations for a coarse-grained concentration field. To deal with diffusion coefficients with an explicit dependence on the concentration values, we generalize the Van Kampen method of expansion of the master equation to field variables. We apply these results to the derivation of equations of phase-separation dynamics and interfacial growth instabilities.

La caverna de José Saramago: imatge platònica versus metafísica

La caverna de José Saramago té com a referència indubtable la imatge de la caverna del llibre VII de la República de Plató, i, tanmateix, Saramago no és un escriptor idealista o metafísic. Aquest article mostra com, tot aprofitant l¿aplicabilitat amb què Plató dota la seva imatge, Saramago defensa la necessitat de saber rebre els missatges de la terra, de la matèria, de no esdevenir presoners en las cavernes daurades de la societat occidental, i d¿esdevenir lliures en la natura, phýsis, i no pas lluny o més enllà, metá, d¿ella.

La caverna de José Saramago: imagen platónica versus metafísica

La caverna de José Saramago tiene como referencia indudable la imagen de la caverna del libro VII de la República de Platón, y, sin embargo, Saramago no és un escritor idealista o metafísico. Este artículo muestra cómo, aprovechando la aplicabilidad con que Platón dotó a su imagen, Saramago defiende la necesidad de saber recibir los mensajes de la tierra, de la materia, de no convertirnos en prisioneros en las cavernas doradas de la sociedad occidental, y de ser libres en la naturaleza, phýsis, y no lejos o más allá, metá, de ella.

The Cave by José Saramago: Platonic image versus metaphysics

The cave by José Saramago has as a certain reference the image of the cave of book VII of Plato's Republic and, however, Saramago is not an idealistic or metaphysical writer. This article, taking advantage of the applicability with which Plato endowed his image, defends the urge to be open to the messages sent by the earth, by matter, the urge not to become prisoners in the golden caves of the Western society and, finally, the urge to find our freedom in Nature, phýsis, and not far or beyond, metá, it.

La caverna de José Saramago: imagen platónica versus metafísica

La caverna de José Saramago tiene como referencia indudable la imagen de la caverna del libro VII de la República de Platón, y, sin embargo, Saramago no és un escritor idealista o metafísico. Este artículo muestra cómo, aprovechando la aplicabilidad con que Platón dotó a su imagen, Saramago defiende la necesidad de saber recibir los mensajes de la tierra, de la materia, de no convertirnos en prisioneros en las cavernas doradas de la sociedad occidental, y de ser libres en la naturaleza, phýsis, y no lejos o más allá, metá, de ella.